Active transendothelial transport of albumin. Interstitium to lumen

Abstract

Cultured porcine pulmonary artery endothelial monolayers actively transport albumin from interstitium to lumen. The active process favors interstitial to luminal transport by a factor of 10 even in the face of a 2:1 luminal:interstitial albumin gradient. The active process is abolished by treatment with 1 mM sodium cyanide. Dextran is not actively transported. This process could be important in determining transvascular fluid balance and transfer of macromolecules across the endothelium.